1. Field of the Invention
This invention relates to a fluorine-containing elastomer composition, and more particularly to a fluorine-containing elastomer composition having a good stock storage stability and capable of producing a vulcanized product with improved vulcanized product properties and compression set.
2. Description of the Prior Art
The vulcanized product of fluorine-containing elastomer have useful characteristics in heat resistance at an elevated temperature, chemical resistance, oil resistance, weathering resistance, etc. and has been in rapidly increasing need in the form of sealing materials such as gaskets, O-rings, packings, etc. or hoses, sheets, etc. in the automobile industry, the oil hydraulic industry, the general machinery industry, the aviation industry, etc. In other words, the needs for the vulcanized product of fluorine containing elastomer have been diversified and have become strict in addition to the need for making the molding and processing steps more efficient.
Vulcanization of the fluorine-containing elastomer was initially carried out with polyamine-based derivatives such as hexamethylenediamine carbamate or methylenebis (cyclohexyl) amine carbamate, but these vulcanization systems had such disadvantages as poor scorch resistance (processing stability and storage stability) or poor compression set of vulcanized product. Thereafter, a process for crosslinking with a polyhydroxyaromatic compound in the presence of a vulcanization promoter and an acid receptor was proposed as a vulcanization system capable of improving these disadvantages and has been commercially utilized up to now.
The vulcanization promoter for use in the vulcanization system includes a quaternary phosphonium salt compound [Japanese Patent Application Kokai (Laid-open) No. 47-191], a quaternary ammonium salt compound [Japanese Patent Publication No. 52-38072 and Japanese Patent Application Kokai (Laid-open) No. 47-3831], a quaternary ammonium salt compound of 8-alkyl (or aralkyl)-1,8-diazabicyclo [5,4,0]undec-7-ene [Japanese Patent Publication No. 52-8863 and Japanese Patent Application Kokai (Laid-open) No. 48-55231], a combination thereof with such an amount of 1,8-diazabicyclo [5,4,0] undec-7-ene as not to substantially vulcanize the fluorine-containing elastomer (Japanese Patent Publication No. 57-20333), etc.
Even with these vulcanization systems, the compression set of vulcanized products is not at a thoroughly satisfactory level particularly at an elevated temperature and also the stock storage stability is not satisfactory.
As a result of extensive researches for fluorine-containing elastomer compositions having a stock storage stability and capable of producing a vulcanized product with improved vulcanized product properties and compression set, the present inventors have found that such a problem can be effectively solved by using a divalent metal amine complex compound represented by the following general formula [I] as a component of the composition.